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Your
query was:
an="B41D-0224"
HR: 0800h
AN: B41D-0224
TI: A synoptic
climatology of desert dust deposition to the alpine snowpack in the San Juan
Mountains, Colorado, U.S.A.
AU: * McBride, K
EM: kem64@dana.ucc.nau.edu
AF: Northern Arizona University, NAU Box 4091,
Flagstaff, AZ 86011
AU: Painter, T
EM: tpainter@nsidc.org
AF: National Snow and Ice Data Center, University
of Colorado 449 UCB, Boulder, CO 80309
AU: Landry, C
EM: clandry@snowstudies.org
AF: Center for Snow and Avalanche Studies, PO BOX
190, Silverton, CO 81433
AB: Currently, collaborative research is underway
in the San Juan Mountains to study the radiative and hydrologic effects of
desert dust deposits in alpine snow. The component described here will
present preliminary results of the development of a synoptic climatology for
winter and spring dust deposition to the alpine snowpack in the San Juan
Mountains of southwest Colorado. An understanding of the climatology of dust
deposition events will improve our capacity to infer the temporal persistence
and magnitude of dust deposition and ultimately its effect on hydrologic and
ecological processes in the San Juan Mountains. We use the Stochastic
Time-Inverted Lagrangian Transport (STILT) model to determine back and
forward trajectories of air parcels. The input data were collected at the
Putney Data site (3757 m) which has been in use for over 30 years and
provides 'free air' wind data as well as ridge crest air temperatures and
humidity. Putney lies 2 km SE of the Swamp Angel Study Plot, east of US
Highway 550 at Red Mountain Pass. The Swamp Angel Study Plot is one of two
extensively instrumented energy balance and radiation sites used in the study
and operated by the Center for Snow and Avalanche Studies (CSAS). STILT
outputs 3-dimensional probability distributions that describe the potential
source regions for air parcels reaching the San Juan Mountains at known times
of dust deposition. We analyze 11 dust deposition events that have been
documented in snow in the San Juan Mountains or Elk Range of Colorado. One
isolated dust event was documented in 1999 in the Elk Range. Subsequently, we
have documented the dust deposition events in winters and springs of 2003, 2004,
and 2005 in the San Juan Mountains. 2003 and 2004 experienced 3 dust events
each but in 2003 the events came in February and April, whereas in 2004 the
events came in late April and mid-May. In 2005, of the 4 dust events, the
first came in late March, the second and third in early April, and the fourth
in early May. There are many similarities in trajectory patterns with some of
these events. Preliminary analysis displays a few weather patterns bringing
dust into the San Juan Mountains. The source of the dust will more than
likely be from several locations with entrainment from source regions in SE
Utah, N and NE Arizona, and extreme NW New Mexico. Moreover, winter and
spring dust events may include intercontinental transport of dust from Asia.
DE: 3300 ATMOSPHERIC PROCESSES
DE: 3309 Climatology (1616, 1620, 3305, 4215, 8408)
DE: 3311 Clouds and aerosols
DE: 3322 Land/atmosphere interactions (1218, 1631,
1843)
DE: 3364 Synoptic-scale meteorology
SC: Biogeosciences [B]
MN: Fall Meeting 2005
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